Currently you can’t change the properties of ::before or ::after with the :hover state.
If you find limitations in the editor you can always use styles in the css panel under style. Generally I always manage to work around this way.
It’s all good. He’s just trying to suggest alternative options in the meantime.
FYI, this Category is really only for discussing potential features. If you want it to officially be considered you’ll want to add it to the idea board (if it’s not already on there)